Amazon SES Can Now Automatically Warm Up Your Dedicated IP Addresses

Edited November, 2017: Since this article was published, we have made some changes that impact the dedicated IP address feature. The article suggests that you can send up to 50,000 emails from an IP address per day. This limitation has since been removed. Your actual sending limit is determined by your use case and your sending practices.

The SES team is pleased to announce that, starting today, Amazon SES can automatically warm up your new dedicated IP addresses. Before the automatic warm-up feature was available, Amazon SES customers who leased dedicated IPs implemented their own warm-up mechanisms. Customers gradually increased email sending through a new dedicated IP before using the dedicated IP to its full capacity. This blog post explains how Amazon SES warms up your dedicated IPs, and how to enable the warm-up feature.

Why do I have to warm up my dedicated IPs?

You must warm up your dedicated IPs before you send a high volume of emails. Many receiving ISPs do not accept emails from an IP that suddenly sends a large volume of email. ISPs perceive this behavior as an indicator of abuse and a possible source of spam. To avoid emails getting dropped or having your sending severely throttled, warm up your IPs by gradually increasing the volume of emails you send through a new IP address. You can find more guidance about the warm up process in the developer guide.

How does Amazon SES warm up my dedicated IPs?

After you enable automatic warm-up, Amazon SES limits the maximum number of emails that you send daily through your new dedicated IP addresses according to a predefined warm-up plan. This automated warm-up process takes up to 45 days. The process ensures that traffic through the newly leased dedicated IP address is gradually increased to establish a positive reputation with receiving ISPs. The maximum daily amount of mail increases from the first day until a maximum of 50,000 emails can be sent from an IP.

When do I have to enable the automatic warm-up?

By default, automatic warm-up is enabled for your account. All newly leased dedicated IP addresses are placed in the automatic warm-up plan. You can disable the automatic warm-up from the Dedicated IPs page in the Amazon SES console. If you are already using dedicated IPs to send emails, go to the Amazon SES console to turn this feature on to take advantage of automatic warm-up.

Note: disabling automatic warm-up stops the warm-up process. All of your IP addresses will be considered fully warmed up. Re-enabling automatic warm-up does not start the warm-up for the dedicated IPs already allocated to your Amazon SES account.

What happens with the emails sent beyond the daily maximum limit from the warm-up plan?

If you enabled automatic warm-up and you are leasing dedicated IPs for the first time, then all emails that you send beyond the pre-planned daily warm-up plan are sent through shared IPs instead. This means that during the warm-up period, Amazon SES uses your dedicated and shared IPs from the Amazon SES IP pools to send your emails. After the warm-up is complete, Amazon SES sends emails only through your dedicated IPs, and the maximum number of emails you can send is limited by your daily email sending quota. For more information, see Managing Your Amazon SES Sending Limits in the Amazon SES Developer Guide.

If you are an existing dedicated IP customer requesting additional dedicated IPs, emails beyond the daily maximum limit per dedicated IP in the warm-up plan are sent only through dedicated IPs already allocated to your account.